On June 3, 1965 Edward H. White II became the first American to step
outside his spacecraft and let go, effectively setting himself adrift
in the zero gravity of space. Photo courtesy of NASA-GRIN
DataBase Number: GPN-2000-001180

Interest in rockets goes back to ancient times when the Chinese used
rockets that burned solid fuel for entertainment and for warfare. The
British and other Europeans used rockets in the 19th century for military
purposes. They were also used for peaceful purposes such as for launching
life-saving equipment from shore into the water to rescue sailors. A major
problem was that these early rockets used solid propellants, which lacked
much power, and they were unguided, meaning that they rarely hit their
target.

In the 20th century engineers began developing liquid-fueled rockets
and guidance systems. In World War II the Germans succeeded in inventing
rockets that could be guided to more distant targets with rough accuracy
(the ability to hit city-sized targets 100 or more miles away). When the
war ended, hundreds of German rocket experts came to the United States
and were instrumental in developing the American space program. The Soviet
Union also used German rocket experts, but did not incorporate these people
into their own space program. After obtaining their knowledge, the Soviets
confined them to Germany and allowed them to conduct only non-rocket research.

Dr. Wernher von Braun stands in front
of a Saturn IBM launch vehicle at Kennedy Space Flight Center. Dr.
von Braun led a team of German rocket scientists, called the Rocket
Team, to the United States, first to Fort Bliss/White Sands, later
being transferred to the Army Ballistic Missile Agency at Redstone
Arsenal in Huntsville, Alabama.Photo courtesy of NASA:
MSFC Center Number: 6863092 GRIN DataBase Number: GPN-2000-000045

Three people are generally considered the fathers of modern spaceflight-Austrian
Hermann Oberth, Russian Igor Tsiolkovsky, and American Robert
Goddard. All three worked in relative isolation from each other during
the early part of the 20th century. Oberth and Tsiolkovsky were largely
theorists, writing about orbits and the possibility of space travel. Tsiolkovsky
wrote about space stations. Both men's writings influenced many people,
particularly in their own countries, to believe that spaceflight was possible.
Unlike Oberth and Tsiolkovsky, Robert Goddard was more of a hands-on engineer
than a theoretician. He was the first person to research liquid-fueled rockets
and developed several gasoline-fueled experimental rockets that he fired
at a test range near Roswell, New Mexico. But because he was reclusive he
did not pass many of his accomplishments on to others and did not train
younger engineers how to build rockets; this may have slowed the progress
of rocketry in the United States.

Spacecraft and spaceflight missions fall into three main categories:
human spaceflight, Earth-focused spaceflight, and astronomical and planetary
spaceflight. The first vehicle launched into space was Sputnik, which
the Soviet Union shot into orbit in October 1957. Sputnik was the opening
round in what became known as the "Space Race," where the United States
and the Soviet Union competed to achieve various firsts in space in order
to demonstrate the superiority of their political and economic systems
and their way of life. The Space Race continued for the next three decades,
but lost considerable momentum by the 1970s and 1980s. Spaceflight is
flight that occurs beyond the Earth's atmosphere using vehicles called
spacecraft. Spacecraft can orbit around another body-these are called
satellites-and can also travel between and beyond planets into the distances
of outer space. In common usage, satellites refer to spacecraft that do
not have a crew on board. These are often called unmanned or robotic spacecraft,
and robotic spacecraft that travel to other planets are often called space
probes.

The Cold War competition between the USA and USSR sometimes lead to
periods of cooperation: This scene was photographed with a handheld
70mm camera from a rendezvous window of the American Apollo spacecraft
in Earth orbit during the Apollo-Soyuz Test Project (ASTP) mission.
It shows the Soviet Soyuz spacecraft contrasted against a black-sky
background with the Earth's horizon below. Photo courtesy of NASA GRIN
DataBase Number: GPN-2002-000155

In 1961 the Soviets sent the first human into space-Yuri Gagarin. Human
spaceflight quickly became the main aspect of competition in the Space Race,
and the most expensive. Although the Soviets undoubtedly won the opening
rounds of the Space Race, the United States caught up quickly and by the
mid-1960s had passed them in terms of total hours of humans in space and
other accomplishments. The ultimate achievement was the landing of Neil
Armstrong and Edwin "Buzz" Aldrin on the moon in 1969. It was this Cold
War competition, rather than a strong interest in science or the mysteries
of space, that served as the incentive for both countries to invest the
large amounts of resources that they have in their respective space programs,
and especially in their human spaceflight programs. Once the Cold War ended
by 1991 with the collapse of the Soviet Union, money for spaceflight decreased
and in many ways, the continuing space programs of the United States and
Russia are a result of political and bureaucratic inertia, with tens of
thousands of jobs depending upon continuing spaceflight.

The most ambitious human spaceflight program, from both a technological
and a financial standpoint, is the International Space Station, or ISS,
now being developed by a consortium consisting of Russia, the United States,
Europe, Japan, and others. The ISS involves extensive cooperation between
the United States and Russia and is intended to symbolize the end of Cold
War animosity. But it has proven to be an astoundingly expensive project
and these costs have dramatically reduced its scientific potential. Because
a significant amount of human activity in space involves fixing things
that break, the ISS cannot produce any useful scientific data until it
has a crew size greater than three, which can only be achieved at considerable
new expense. As a result, even today, after the end of the Space Race,
most human spaceflight remains more symbolic than beneficial or practical.
Robotic, Earth-focused spaceflight offers the most direct benefits to
those on Earth. Communications satellites, meteorological satellites and
remote-sensing satellites fall into these categories.

The beginnings
of America's rocket program: Dr. Robert H. Goddard and a liquid
oxygen-gasoline rocket in the frame from which it was fired on March
16, 1926, at Auburn, Massachusetts Photo courtesy of NASA

Communications satellites enable audio, video and data signals to be transmitted
around the globe quickly and efficiently, shrinking the size of the Earth
as people around the world can communicate with each other almost instantaneously.
Meteorological satellites enable scientists to "see" the Earth's atmosphere.
Instruments on board meteorological and other atmospheric research satellites
measure and sample the atmosphere from great distance, identifying areas
that may lead to severe storms. These satellites allow meteorologists and
researchers to forecast major weather events like hurricanes and track their
development and movement, and warn people to get out of the way. They have
saved countless lives. Atmospheric observation satellites are also used
to monitor ocean currents and temperature and to analyze trends such as
global warming, ozone destruction, and pollutants in the atmosphere. They
have played a major role in the debate over human impact on the environment.

Remote-sensing satellites view the Earth's surface. They are used for
agricultural and land-use monitoring. But their primary use is military.
Reconnaissance satellites, operating in polar orbits, are used to monitor
troop movements, construction, and other military activities. Surveillance
satellites in geosynchronous orbit watch for missile launches. Signals
intelligence satellites in similar orbits listen for the faint whispers
of electronic signals such as radio transmissions and radar.

Some spacecraft study the sun as well as its interaction with the atmosphere.
This information can be of general scientific use and can also be important
for understanding weather and global climate change. Astronomical spacecraft
operate in Earth orbit and observe distant objects like stars and galaxies.
Away from the distortions produced by the atmosphere, large observatories
like the Hubble Space Telescope can see farther than any Earth-based telescope
could ever see. They are investigating how the universe began, how it
has evolved, its age and other mysteries.

Astronaut Buzz Aldrin, lunar module pilot of the first lunar landing
mission, poses for a photograph beside the deployed United States
flag during an Apollo 11 Extravehicular Activity (EVA) on the lunar
surface. The Lunar Module (LM) is on the left, and the footprints
of the astronauts are clearly visible in the soil of the Moon. Astronaut
Neil A. Armstrong, commander,and first man to set foot on the moon,
took this picture with a 70mm Hasselblad lunar surface camera Photo courtesy of NASA GRIN
DataBase Number: GPN-2001-000012

Planetary exploration spacecraft leave Earth orbit to explore the inner
and outer planets as well as other objects in the solar system. Spacecraft
have been sent to every planet in the Solar System excluding Pluto, and
more recently to several comets and asteroids. The Moon remains the only
object besides Earth to have been visited by humans. Mars is the most heavily
explored planet due primarily to its similarity to Earth and its relative
proximity to Earth. Mars, which had abundant water millions of years ago,
may have once supported life and evidence of past life on Mars would be
a major scientific discovery. During the 1990s, scientists became increasingly
interested in Jupiter's moon Europa, which has a vast ocean under its ice
and is therefore a prime site in the search for life.

The Space Shuttle is a unique and highly versatile launch vehicle. It
can be used to carry a payload in its cargo bay that is released and launched
into space. The Space Shuttle presently is the only reusable launch vehicle,
and in fact the only reusable spacecraft. Because expendable launch vehicles
are so expensive, the Space Shuttle was intended to lower the costs of
launching a pound of payload into space. It has dramatically failed to
do this. The United States has spent considerable money trying to develop
cheaper reusable launch vehicles, or RLVs, to lower the cost of launching
payloads, but has not been successful so far. More extensive exploitation
and exploration of space, including things like space tourism, is not
possible until the cost of reaching space comes down dramatically.

The Space Shuttle Columbia arrives
at Pad 39B early in the morning after being rolled out of the Vehicle
Assembly Building the night beforePhoto courtesy
of NASA GRIN DataBase Number: GPN-2000-000669

Launch vehicles are virtually the same as rockets and missiles. The term
"missile" is usually used when the vehicle does not actually enter orbit
and when the payload-what the launch vehicle is carrying and propelling
into space-is some sort of weapon. Most modern launch vehicles consist of
more than one stage. This means that two or three rockets are joined together,
each with its own rocket motor, to form a single launch vehicle. During
launch, these stages fall off as the rocket motors are fired and as the
payload is gradually maneuvered into its proper position. When a launch
vehicle or rocket releases its payload, it is said to deploy its payload.
Modern rockets are extremely expensive to operate, frequently costing thousands
of dollars per pound of payload placed in orbit.

Although the United States and Russia (formerly the U.S.S.R.) have led
in spaceflight, other countries have developed their own space programs
and are also participating more and more in cooperative space missions.
Astronauts from numerous countries have flown into space aboard Russian
and American spacecraft and work on the International Space Station. By
the late 1990s, China had started development of its Shenzou spacecraft
to transport several humans into space, and was reported to be working
on its own space station. Spaceflight has a unique ability to capture
the imaginations of all kinds of people who will probably never go into
space themselves.

A longer and unedited version of this essay, originally
titledSpaceflight-An
Overview, by Dwayne Day, can be
found at the U.S. Centennial of Flight's website